Control device for wireless signaling.



E. H. COLPITTS.

CONTROL D-EVlCE FOR WIRELESS SIGNALING.

APPLICATION FILED SEPT. II. 1915.

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6.21% .M& Edwm (o/pi/Ts.

UNIT D sTATEs ,PATENTOFFICE.

Enwm i1. conm'r'rs, or EAs'r QRANGE, N W JERSEY, Assmno'R, BY MESNEASSIGN- MENTS, T0 WESTERN ELEc'rRIe COMPANY, INCORPORATED, A'coRroRA'rroN 0E NEW YORK.

To all whom it may concern:

Beo-itknown that I, EDWIN H. Conrrr'rs, a subject of the Kingof GreatBritain, residing at East Orange, in the county of Essex and State ofNew Jersey, have invented certain new and useful Improvements in ControlDevices for Wireless Signaling, of which the following is a full, clear,concise, and exact description.

This inventionrelates to the control, for signaling and other purposes,of a large current obtained from the output circuit of a thermionicamplifier. The object is to reduce the power consumption to a minimum orsmall value and to obtain a maximum output from a given amount ofapparatus.

The results are obtained by so arranging the circuit that the spacecurrent flows in the amplifier tubes only during the time'that signalimpulses are being sent.- This might be accomplished by making iandbreaking the output or high power, circuit of the amplifier, but thisinvolves the interruption or breaking of a circuit in which a largecurrent at a high potential may be flowing. The desired result can beobtainedbetter by an arrangement by means of which the voltage of thebattery in the input or grid circuit has such a value that the spacecurrent, that is, the current in the output circuit, is made very small.In other words, provision is made whereby the voltage applied to thegrid or input circuit of the amplifier is changed at the instant ofsignaling from such a value as causes a mini- ,mum energy loss in theoutput circuit to a.

value which permits of. normalflow of current in the said circuit. Thismay be accomplished in a variety of ways .and very readily for the rea nthat the normal power absorbed in he input circuit. of a .thermionicamplifier is very small. I

The figure of the drawing shows one arrangement of circuits bywhichsthe'desired result is obtained. v

Referring to the figure, 1 represents a'. generator of high frequencyoscillations of low power, which is connectedto the -pri-'- mary of atransformer 2; the secondary of said transformer being connected to theinput circuit of a thermionic amplifier 3; the

Specification of Letters Patent. Application filed September 11,1915.Serial No. 50,171. R

circuit of the high The compound key or switch may be oper- CONTROLDEVICE oR WIRELESS sreiunme.

"Patented Sept. 19 1916.

SITE

usual grid. The output circuit is connected.

from the plate electrode 6 through the inductance 8, the battery 7 andthe filament 5. For signaling purposes, the inductance 8 is inductivelyconnected to the inductance 9, which in turn is connected to thesignaling system. This signaling system may consist of any wire systemor may be used for spacetelegraphy as shown in the figure, in which 10represents the elevated antenna or other suitable radiating system and11 represents, the usual earth connection for such a system.

Connected to the input terminals of the amplifier and in parallel to thesecondary of the transformer 2 is a circuit containing a battery 12,which is the :usual battery for determining the potential appliedbetween the electrodes 4 and 5. In this invention,

battery 12 has a sufliciently highvoltage to reduce the space currentflowing between the electrodes 6 and 5, from thebattery 7 to a' zero ora relatively small value; In order to transmit signaling currents, it isnecessary to reduce the voltage impressed on the input circuitsufliciently to permit the flow,

of the normal spacegcurrent. In order to .accomplish this the followingarrangement has been found useful: A switch or key 13 placed inthecircuit of the battery, and .a large resistance 14 of severalthousand ohms-or moreis placed. in shunt ,to, this. key. A conductor 15leads from some intermediate point 16 of the battery 12, the free end.of said conductor-15 being placed in juxtaposition to the springterminal 17, which also forms one terminal of the switch 13.

It has been found desirable also, but not necessary, to place a key orswitch 18 in the uency generator.

,key 21, which closes a circuit containing the said key, battery 22 "andthe winding of the relay..' Inthe circuit of the secondary of thetransformer 2 is placed condenser 23.

A similar condenser 24 is placed in shunt to the battery 7. A choke coil25 is placed in the circuit of the battery 12.

between the electrodes 5 and 6. Upon clos- Y ing the key 21, the switch13 is opened and the member 17 is moved to make contact withthe terminal26 and also to close the switch at 18. This operation brings the point16 of the battery 12 into electrical connection with the terminal at ofthe amplifier. Conductor 15 is placed at such a point 16 of the batterythat the voltage, which is now impressed on the input circuit of theamplifier, is sufficiently small to permit the normal flow of spacecurrent through the am plifier. At the same time the .closing of theswitch 18 permits the transfer of high frequency, low power oscillationsinto the input circuit of the amplifier. The whole operation results ina flow of amplified high frequency oscillations in the output circuit ofthe amplifier.

The purpose of the high resistance 14 is to prevent that portion of thebattery 12,

which is not used when signaling, from being short-circuited. Thecondenser 23 is to prevent the discharge of the battery 12 through thesecondary of the transformer 2, and the choke coil 25 is inserted inorder to prevent the discharge of the high frequency oscillations fromthe transformer through the battery circuit. The condenser 24 is used toafford a path of low impedance for the high frequency oscillationsaround the battery 7 and also to form a short circuit for transient highfrequency disturbances in a generator of high frequency oscillations ofthe battery 7.

.For simplicity, this invention has been described and shown for oneamplifying tube only. It is to be understood, however, that in generalone such tube will not supply sufficient power for radio telegraphy, andfor this reason there will in general be a large number of such tubesconnected in parallel in any suitable manner, such, for example, as is.shown in patent to Arnold, 'No. 1,129,943, March 2, 1915.

It is obvious that the method is not limited to simple hand sending, butcan be employed wherever the sending ofsignals involvestaninterrupted-outpu It is tobe understood that while I have shown anddescribed invention as ap plied to a signaling system, it is not to beso. limited as to its application, for itis apparcut that the inventionmay be used in any -i place where it is desired to alternately changethe output of such an amplifier as shown from a minimum to a maximumvalue, or the reverse.

What is claimed is:

1. In a system for amplifying weak impulses, an amplifier of the audiontype, the output circuit of which is adapted to carry a space current; asource of voltage connected to the input circuit of said amplifier; acircuit for supplying said weak impulses to the said input circuit, andmeans to control the impression of said impulses on the input circuit,said means being adapted to vary the amount of voltage of said sourceimpressed upon the input circuit of the amplifier whereby the spacecurrent is reduced to a small value when the weak impulses are 3. In ahigh frequency signaling system;

a generator of high frequency oscillations of low power; an amplifierhaving an input and an output circuit, said generator being connected tothe input circuit of the amplifier; a source of voltage-connected to theinput circuit of the amplifier, said source having suiiicient voltage toreduce'the output current of the amplifier to a small value andsignaling means for reducing the voltage of the source impressed on theinput circuit of the amplifier, when signaling, to permit a large outputcurrent.

4. Ina high frequency signaling system low. power; a'thermionicamplifier of the audion type, said generator being connected to theinput circuit of the amplifier; a battery connected to the input circuitof the amplifier and a switch adapted, when not signaling, to impressthe whole battery voltage upon the input circuit of the amplifier,whereby the space currentis reduced to a small value and adapted, whensignaling, to impress a portion only of said battery voltage upon theinput circuit of the amplifier.

5. In a high frequency signaling system, a generator of high frequencyoscillations of low power; a thermionic amplifier of the audion type,said generator'being connected to the input circuit of theamplifier; abattery connected to the .input circuit of the amplifier and parallel tothe generator and a switch adapted, when not.signaling, to impress thewhole batteryyoltage upon the input circuit of the amplifier, wherebythe space current is reduced to a minimum and adapted, when signaling,to impress a portion only of said battery voltage upon the input circuitof the amplifier.

6. In a high frequency signaling system, a generator of high frequencyoscillations of low power; a thermionic amplifier of the audion type; abattery; said generator and battery being connected to the input circuitof the amplifier and a switch adapted, when signaling, to impress aportion only of said battery voltage upon the input circuit of theamplifier and to close the generating circuit, and adapted, when notsignaling, to open the generator circuit and to impressthe whole batteryvoltage upon the input circuit of the amplifier, whereby the spacecurrent in the amplifier is reduced to a minimum when not transmittingsignals.

7. In a high frequency signaling system, a generator of high frequencyoscillations of low power; a thermionic amplifier of the audion type,said generator being connected to the input circuit of the amplifier; abattery connected to the input circuit of the amplifier and in parallelto the generator, and a switch adapted, when signaling, to impress aportion only of said battery on the input circuit of the amplifier andto close the generator circuitand adapted, when not signaling, to openthe generator circuit and to impress the whole battery voltage upon theinput circuit of the amplifier, whereby the space current in theamplifier is reduced to a minimum when not transmitting signals.

8. In a high frequency signaling system, a generator of high frequencyoscillations of low power; a thermionic amplifier of the audion type,said generator being connected to the input circuit of the amplifier; abattery connected to the input circuit of the amplifier and in parallelto the generator anda magnetically operated switch adapted, whensignaling, to-shunt a portion of the battery, to impress the remainderof said battery voltage upon the input circuit of the amplifier and toclose, the generator'circuit, and adapted, when not signaling, to openthe generator circuit and to impress the whole battery voltage upon theinput circuit of the amplifier, whereby the space current in theamplifier is reduced to a minimum when not transmitting signals.

9. In a high frequency signaling system a generator of high frequencyoscillations of low power; a thermionic amplifier of the audion type,said generator being connected to the input circuit of the amplifier; abattery connected to the input circuit of the amplifier and inparallelto the generator; a choke coil and a resistance in series with saidbattery and a magnetically operated switch adapted, when signaling, toshunt a portion of said battery through said resistance, to impress theremainder of said battery upon the input circuit of the amplifier and toclose the generator circuit, and adapted,

when not signaling, to open the generator circuit, to short circuit theresistance and to impress the whole battery upon the input circuit ofthe amplifier, whereby the space current in the amplifier is reduced toa minimum when not transmitting signals.

10. In a high frequency signaling system, a generator of high frequencyoscillations of low power; a thermionic amplifier of the audion type; acondenser; a transformer, the primary of which is in the generatorcircuit and the secondary of which is connected,'in series through. thecondenser, to the input circuit of said amplifier; a battery connectedto the input circuit and in parallel to the secondary of thetransformer; a choke coil and a resistance in series with said batteryand a magnetically operated switch adapted, when signaling, to open theshort circuit, to shunt a portion of said battery through saidresistance, to impress the remainder of said battery on the inputcircuit of the amplifier and to close the generator circuit, andadapted, when not signaling, to short circuit the resistance in serieswith said battery and to open the generator circuit, whereby the spacecurrent in the amplifier is reduced to a minimum when not transmitting.

In witness whereof I hereunto subscribe my name this 8th day ofSeptember, A. D.

EDWIN H. COLPITTS.

